Biofilm formation and planktonic proliferation by undesired microorganisms are well known phenomena in domestic as well as industrial settings. For instance, toilet bowls harbor undesirable bacteria on surfaces and in solution that can contribute to a noticeably fouled appearance of the bowl. Further, the presence of undesired microorganisms in the bowl may cause dispersion of aerosols when flushing. Massive biofilm formation and planktonic proliferation in water systems, e.g., pipes, pumps and vessels, are known to cause health care risks, corrosion, and aesthetic problems.
Preventing or reducing biofilm formation and/or planktonic proliferation by undesirable microorganisms traditionally requires the use of dispersants, surfactants, enzymes, microbes, antimicrobial agents, biocides, boil-out procedures, and/or chemicals.
U.S. Pat. No. 5,171,591 concerns controlling or eliminating undesired bacteria in or on certain food or food contact surfaces using parasitic bacteria of the genus Bdellovibrio. 
U.S. Pat. No. 5,242,593 concerns a method for reducing the buildup of slime and/or film in water circulation systems by adding non-sessile microbes in single form to the circulating water.
U.S. Pat. No. 5,360,517 discloses a process of regulating the growth of the microbial/bacterial flora existing in an aqueous papermaking circuit/process stream comprising introducing an effective disinfectant amount of bacteria of the species Staphylococcus carnosus. 
U.S. Pat. No. 5,863,882 concerns liquid cleaning and sanitizing formulations comprising a sanitizing composition, viable Bacillus spores, and surfactants capable of reducing four pathogenic microorganisms.
AU Patent No. 719544 concerns a method of controlling the number of pathogenic bacteria in a body of water by adding non-pathogenic gram positive bacteria.
WO 2006/031554 disclose a method of preventing, removing, reducing or disrupting biofilms on surfaces by contacting said surface with an alpha-amylase derived from a bacterium.
Though methods of reducing and preventing biofilm formation and planktonic proliferation of undesired microorganisms are known in the art there is still a need for methods and compositions for doing so.